Usually they tend to toss lefty talking points out there.
And they try to be clever about it.
They evade direct answers, they try to redirect the discussion, they make hyperbole comments and exaggerate the situation.
Or, in some cases, they come right out and make outrageous racist comments.
Usually those guys are posting someplace else and linking back to their own comments as prooof that conservatives are racists.
(Little Green Footballs is famous for that one.)
There are lots of ways to tell, the formula for detection isn’t really easy to eplain in one post.
Some of it is learne through experience as well.
We had a Delphi Technique troll here the other day, he was a college professor (according to his facebook page he was a “rhetoritician”) in Vancouver.
We also have seen the rise of the “concerned troll”.
Well guess it’ll take a bit of time to notice those things.
And when leftist trolls are proven utterly wrong with sources, facts and so on - they become silent. They never admit they are proven wrong.
Then after a while, they pop up with the exact same proven-wrong lies, often on another thread. Just as though their lies had not be pulverized.
That’s a constant with them.